For realizing, for example, customized colors that are employed for example, for company logos, it is meaningful to produce colors from a few primary colors in order to achieve the customized color (referred to below as target color). In this way, specific target colors can be achieved with a few primary colors that are actually present. Predictions about the required composition of the primary colors for achieving specific target colors must be made before production (for example, mixing with the assistance of agitators). This procedure is called color formulating.
Color formulating is know in conventional printing (for example, offset printing) and is frequently employed therein (for example, Billmeyer, F. W., Saltzman, M., Principles of Color Technology, New York, John Wiley & Sons Inc., 2000, Berns, R. S. (editor), 3rd edition, English). With the assistance of complex mathematical models and calibration data for the unmixed primary colors that are in fact physically present, for example CMYK, attempts are thereby made to make predictions about mixed colors. The basis for these calculations is that topically uniform mixed colors are present that can absorb and scatter light. Boundary surface effects and dependencies of the color layers on layer thickness are thereby also taken into consideration. Designationally achieving the target color without such formulating procedures is not possible because of the great number of colors (there are approximately 2 million different colors). The preparation and testing of recipes is complicated and time consuming in all printing processes.
The production of the reference proofs of the primary colors is very involved and is subject to fluctuations in all conventional color formulating systems. The determination of the required parameters is only approximately possible, and taking the underlying physical relationships mathematically into consideration is only possible given the application of approximations.
Customized colors are also produced with digital (for example, electrophotographic) printing methods. Given these methods, toner is often employed for the inking. The toner particles thereby comprise a size from a few μm through several 10 μm. Since the toner particles comprise the color of the respective basic toner and the toner diameter is large compared to the wavelength of light, a uniform color can no longer be assumed in these cases; the assumptions that are applied in color formulating in conventional printing no longer apply.
Some approaches with commercially available formulating systems have exhibited extremely great deviations between predicted color and color actually achieved given the employment of digital printing systems.